The engine "pings" when under load. I believe the correct term is pre-ignition (?). What causes this? is it bad for the engine and how do I solve this problem?

Thanks

John

 

your timing may not be correct. check that first.

 

My mechanic suggested using 89 octane for a tank load, which I am doing, before doing tune up and timing. Seems to help (maybe psychological?): engine seems to be running more smoothly with less pinging, tho' it is still pinging under load. Could the octane have this effect?

 

Not to overly sure about your car but my new 83 turbo was pinging anytime I gave it a good amount of pedal and after poking around I realized that the vacuum advance diaphragm was stuck closed and I attached a clean hose and worked it by lung power till it was operating smoothly and now my car runs awesome and has power all the way to redline if I wanted to push it that hard. Pop the cap of the distributor and remove the hose from the vacuum pot attach a clean hose and give it a nice pull wia your mouth and watch for the arm that goes into the vacuum pot to move alittle.